Ian, in the FDC (2nd ed.), Troop states that the Ilford Replenishing Developer is regarded by some as identical to Microphen. Here are the formulas for both, taken from the FDC pp 163-164:
Chemical |
ID-68 |
Replenishing Dev. |
Sodium sulfite |
85 |
100 |
Hydroquinone |
5 |
5 |
Borax |
7 |
3 |
Boric acid |
2 |
3.5 |
Phenidone |
0.13 |
0.2 |
Potassium bromide |
1 |
1 |
Water to make |
1 L |
1 L |
.
Can you comment on these two formulas regarding how close they are to Microphen and their image quality?
Also, Troop prefers the Replenishing Dev. because its pH is lower. Do you have a preference?
Mark
Mark, the Morgan & Morgan Photo Lab Index assumed that the Axford-Kendall Fine Grain PQ developer formula was Microphen, in fact it's the formula of Autophen a PQ variant of ID-11/D76. That myth persisted in other US publications.
During the mid to late 1950s there were a number of articles in the BJPabridgeded in the annual BJP Almanacs which shed light on the formulation of Autophen from a PQ version of ID-11 in the Kendal Phenidone patent. One aspect they highlighted was testing chemical exhaustion to formulate replenishers, two were devised one for topping up, the other bleed replenishment.
The advantage of a PQ version of ID-11 was it was not affected by Bromide build up so had a far greater capacity, and could be replenished for a long time, one lab years without mixing fresh..
One thing noticed was the slight speed increase of Autophen and a new developer was formulated to exploit this further, dropping thew Sulphite level by 20% helps boost film speed. as many found using Adox Borax MQ, or Agfa 44 (Agfa Ansco 17), compared to ID-11/D76.
This is from my 1960 book of Ilford Forulae. Autophen was only sold in larger sizes, it was a fixed development time for most films. If I find the book I'll scan page 7
Ian